Rotary refiner for relatively high density fibrous material



May 24, 1966 E. P. ARPIN, JR I 3,

ROTARY REFINER FOR RELATIVELY HIGH DENSITY FIBROUS MATERIAL 'Filed Nov. 15, 1962 [III/III INVENTOR. KIM/(4V0 A 48 (/6.

' D BY v f" ;ATTORNEYS United States Patent 3,252,665 RGTARY REFINER FOR RELATIVELY HIGH DENSITY FIBROUS MATERIAL Edmund P. Arpin, .lr., 587 E. Wisconsin Ave.,

Neenah, Wis. Filed Nov. 15, 1962, Ser. No. 237,980 5 Claims. (Cl. 241245) This invention relates to improvements in rotary refining machines which are used to refine wet, fibrous material, such as pulp, paper stock and the like.

The present invention has particular application to a rotary refiner of the type having a cylindrical abrasive liner and a series of rotor elements carried on a central shaft and movable against the abrasive liner by centrifugal force upon rotation of the shaft. It has been found that for this type of machine to operate at its highest efficiency there is an optimum stock consistency which is higher than that normally fed to stock refiners. The reason for this is that the water, if above a certain percentage, tends to act as a cushion which prevents the pulp fibers from being most efficiently acted upon by the refining elements of the machine. A refiner utilizing means for providing a relatively higher stock density is disclosed in my US. Patent No. 2,927,738 issued March 8, 1960. The present invention is particularly concerned with improvements in a high density defining machine of the type disclosed in my prior patent. 'It has been discovered that it is highly advantageous in a high density refining machine of the type shown in my prior patent to provide material impelling vanes having impelling surfaces disposed at an angle to the plane of rotation of the vanes in association with the rotating refining elements within the refining section of the machine.

It is therefore an important object of the present invention to provide an improved high density type rotary refining machine.

It is a further object of the present invention to provide a rotary refining machine capable of processing material such as raw wood chips, cooked wood chips, pulp screen rejects or an unrefined wood pulp at an optimum relatively high density of about 9% and above.

Other objects, features and advantages of the present invention will be apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIGURE 1 is a somewhat diagrammatical vertical sectional view of a high density rotary refining machine in accordance with the present invention; and

FIGURE 2 is a fragmentary elevational view of a backingelement of a rotary assembly of the rotary refiner of FIGURE 1.

The present invention is illustrated as being embodied in a rotary definer machine indicated generally by the reference numeral 10, including a generally cylindrical shell or casing 11 which may be supported with its longitudinal axis extending in a generally horizontal orienration upon suitable supporting legs (not shown). The shell 11 is provided with end plates at the opposite longitudinal ends thereof such as end plate 13 at the discharge end of the machine. High density stock supply means such as indicated at 14 may be located within the inlet end plate of the machine and such high density stock supply means may correspond to that disclosed in my US. Patent No. 2,927,738. The high density stock supply means of my prior patent operates to substantially increase the density of the material supplied to the machine by subjecting the material to an extracting operation which removes a controlled amount of water from the stock at the inlet end of the machine prior to feeding "Ice of the material into the refining section of the machine within the casing 11.

A hollow shaft 19 extends axially through the refiner machine and is journalled in suitable bearings at the opposite ends of the machine. The shaft 19 is adapted to be rotated by means of a grooved pulley (not shown) secured on the shaft externally of the end plate at the inlet end of the machine.

The shell 11 is provided internally with a liner 22 composed of a number of ring sections 23 which are formed of suitable abrasive material, such as stone, metal or a synthetic ceramic of an abrasive type. A series of equally spaced helical grooves 24 may be provided extending generally longitudinally of the machine and forming continuous passages along the inner surfaces of the ring sections 23 between the inlet and outlet ends of the machine.

In the machine illustrated, a plurality of rotor assemblies 25 are mounted in peripheral sets of four each for rotation with the hollow shaft 19. Each rotor assembly includes a refining element 27 secured in a backing member 28 which is pivotally mounted to a collar 26 keyed to the shaft 19, for example as indicated at 27. The back- I ing'plates 28 have spaced ear portions 31 which are pivot ally secured to flange parts 32 on collar 26 by means of pivot pins such as indicated at 3 3. As the shaft 19 is rotated in the direction of arrow 35 the rotor assemblies move outwardly by centrifugal force causing the refining elements 27 to coact with the abrasive surface of the liner rings 23 to refine the fibrous material. Both the liner rings 23 and the refiner element 27 may be formed of stone, metal or a synthetic ceramic of an abrasive type.

A positive acting linkage for maintaining a minimum clearance at all times between the surface of each refining element 27 and the abrasive surface of the liner rings 23 comprises a lever arm 37 pivotally mounted on the pin 33 and engaging at one end with a bracket 39 carried by the backing member 28 and at the other end disposed in abutting contact with the end of a push rod 42 slidably mounted in aligned radial apertures in the hollow shaft 19 and collar 26.

As a means of controlling the radially inward and outward movement of the push rod 4-2, there is provided a series of fr'usto-conical wedge members (not shown) secured to telescoping rods extending longitudinally inside the shaft 19. Further details of the construction and operation of. a refining machine to which my novel rotor construction may be applied, may be found by reference to my US. Patent No. 2,475,869.

The backing plate or member 28 comprises a substantially flat central portion .52 with an overhanging ledge 53 which extends across the leading end of the backing member forming a seal against which the corresponding port-ion of the refining element 27 is pressed. At both sides of the backing member a wall portion 55 extends from the flat central portion 52.

A metal pressure pad as indicated at 59 is disposed across the trailing edge of the refining element 27 with a pad of cushioning material between the adjacent surfaces of the metal pad 59 and the refining element 27. This cushioning pad may be of a material such as rubber,

soft metal alloy or plastic to protect the refining element 27. A series of wedges 62 are disposed between a marginal flange 63 at the trailing edge of the backing member and the pressure pads 59. Stud bolts 65 pass freely through an opening in each wedge 62 and are in threaded engagement with the associated backing member 28.

stock supply means 14 shown in FIGURE 2 comprises impeller blades 150 secured to and rotatable with shaft 19. Said impeller blades are disposed between the inlet chamber and the refining section of the machine defined by the shell 11. The impeller blades are secured to an annular plate 153 separating the inlet cham'ber from the refining section of the machine, and the annular plate is provided with openings such as 73 in advance of the impeller blades 150 which provide for feed of the high density stock into the refining section of the machine in advance of the refining elements 27 as indicated by the line 70 in FIGURE 1 and by arrow 76 in FIGURE 2. The openings may be arranged so as to supply material in advance of each of the refining elements 27 and the annular plate 153 and openings therein rotate in the direction of arrow 77 in synchronism with the refining elements so as to maintain the specified relationship. The action of the impeller blades 150 tends to force material into the refining section of the machine and along the inner surface of the ring sections 23 to the outlet end of the machine. The positions of the inlet openings in the rotating annular plate have been indicated in phantom outline in FIGURE 1 at 71-74. These openings rotate in the direction of arrows 75 at the same speed as the refining elements 27.

Cooperating with the impeller blades in removing excess liquid from the stock is a perforated ring (not shown) having apertures therethrough leading from the inlet chamber. The liquid drained from the incoming stock may be delivered to the outlet end of the machine as described in detail in my Patent 2,927,738.

For regulating the amount of liquid removed from the stock, as described in my prior Patent 2,927,738 a variable feed pump is connected with the drain from the inlet end of the machine. By regulating the flow of liquid through t-he pump it is possible to control the amount of water removed from the stock in the inlet chamber.

As set forth in my Patent 2,927,738, the following comparison is representative of the results obtained in refining of West Coast bleached kraft pulp at a moderately low consistency (4 to 5% on an air dry basis) and at a relatively high consistency as contemplated in the present invention (9 to 10% on an air dry basis). The rate of feed through the refiner used was in each case 2000 pounds of bone dry stock per hour.

The improved Mullen strength tear factor, and fold qualities resulted solely from the use of the higher consistency, since the same stock was fed continuously at the same rate of feed, in the one case at the normal operating consistency of-4 to 5% through a rotary refiner not provided with my thickening means 14 but otherwise similar to that herein described, and in the other case at the same initial consistency of 4 to 5% through a combined thickener and refining apparatus such as herein described. No auxiliary thickener need be utilized ahead of the thickener means 14. The stock consistency was raised from 4 to 5% to from 9 to 10% within the refiner itself by the action of the cooperating thickening elements of my Patent 2,927,738. The water so removed at the feed end of the refiner was then returned for admixture with the refined stock discharged from the refiner.

Experience has proved that under normal operating conditions, excellent results are obtained in the refining of chemical pulp screen rejects at 7-8% consistency,

and of mechanical pulp screen rejects at 3.5 to 4% consistency, whereas if refined at normal consistencies of 1 to 2%, as delivered from the screens, the results are unsatisfactory.

In accordance with one embodiment of the present invention, the high density rotary refiner of my prior Patent 2,927,738 is provided with material impelling vanes such as indicated at 81-84 having impelling surfaces such as indicated at 86 in FIGURE 2 disposed at an angle to the plane of rotation of the vanes which plane coincides with the plane of FIGURE 1 and is coincident with the direction of movement of the vanes indicated at 87 in FIGURE 2. The impelling vanes 81-84 are preferably located at the inlet sides of the refining elements 27 and preferably rotate at the same speed as the refining elements. Preferably, the vanes are secured to the leading edges 53 of the backing members 28 of each of the rotary refining assemblies 25. It is found that these vanes have a very advantageous effect in assisting the lateral movement of high density stock toward the discharge end of the rotary refiner. With a relatively high stock density of the order of 9%, it is found that the stock mass in the primary stage of refining within the refining section of the machine becomes sutficiently fluid to be acted upon by the inclined faces 86 of the vanes to propel the stock laterally through the refining section. Normally, one vane ahead of each of the individual refining elements 27 of the rotor is sufficient. Additional vanes, however, may be provided, or the pitch of the propelling face 86 may be varied by making the vanes angularly adjustable on the backing members 28 to vary the degree of propulsion in accordance with stock density.

In pulping of raw wood chips, cooked wood chips, pulp screen rejects, or an unrefined wood pulp, it is found that optimum results are obtained at relatively high densities such as 9% or somewhat above this figure within certain definite limits. The material impelling vanes 81- 84 thus enable operation with optimum relatively high densities of the order of 9%.

When in operation on wet or dry material, the interior spaces of the rotor mechanism shown in FIGURE 1 are mainly filled with air, the stock mass being forced out against the shell lining into a relatively thin layer. My prior Patent 2,927,738 relied upon the helical grooves such as indicated at 24 in the shell lining 22 which are inclined so as to tend to move the material toward the discharge end of the machine. This helical grooving, however, did not fully satisfy requirements, and it is now found that the material impelling vanes 81-84 are effective to provide optimum progress of high density stocks through the machine.

Summary of operation When in operation, raw wood chips, cooked wood chips, pulp screen rejects, unrefined wood pulp or the like is supplied from the stock supply means 14 to the refining section of the machine at a relatively high consistency such as about 9% or more on an air dry basis. Generally the present invention is considered applicable to stock consistencies in the range from about 8% to 12% on an air dry basis. The details of a suitable high density stock supply means are found in my Patent No. 2,927,738.

During operation, the shaft 19 may rotate at a speed of about 700 revolutions per minute. The stock is continuously fed from the supply means 14 into the refining-section, for example at the location of openings 71-74 indicated in phantom outline in FIGURE 1 in advance of the respective refining elements 27 of the rotary refining assemblies 25. Material impelling vanes 81-84 rotate with the refining assemblies and are provided with angularly disposed impelling surfaces such as indicated at 86 in FIGURE 2 for effectively moving high density stock through the refining section at the optimum. speed. By way of example, for stock having a consistency of 9 to 10% of an air dry basis, the rate of feed through the refiner is preferably substantially greater'than 2000 pounds of bone dry stock per hour. The interior diameter of the liner 22 of FIGURE 1 is substantially 2 /2 feet in one practical machine in accordance with the present invention. The angle of the impelling surfaces such as 86 relative to the direction of movement indicated by arrow 87 is preferably approximately 30 for a stock consistency of 9 to 10% on an air dry basis. For somewhat higher consistencies, the angle of the surfaces 86 may be increased somewhat as indicated in dash line 86a in FIG- URE 2. The adjustment of the angle may be accomplished by means of a suitable clamping screw 88 which threads into the backing member 28 and which has its head fiush with the radially outer surface of the vanes. The radially .outer surface of the vanes such as indicated at 83a in FIGURES 1 and 2 has a clearance with respect to the liner 22 which is substantially the same as the minimum clearance between the outer surface of the refining elements 27 and the inner turface of the liner 23. Thus, the entire radially outer edge of impelling surface 86 has a substantially uniform clearance gap from the interior surface of the liner 22 which is substantially the same as the clearance of the refining elements 27 with respect to the liner 22.

The backing members 28 may have an overall dimension in the axial direction of the machine of approximately 52 inches so that there may be six sets of rotor assemblies successively ofiset along the shaft 19.

It will be apparent that the vanes such as indicated at 83 in FIGURE 2 may be placed at spaced intervals along the leading edge portion 53 of the backing member 28 so that the inclined material impelling faces 86 would be located at successive axially spaced intervals along the leading side of each of the refining assemblies.

The liquid removed from the stock at the inlet end of the machine may be delivered to the outlet chamber of the chamber or mixed with the stock discharged from from the refining section of the machine at some other suitable point.

While in my Patent 2,927,738, the perforated ring at the inlet section of the machine is described as being stationary, it will be understood that this ring may be replaced by a bowl including a cylindrical perforated plate adjacent the inlet end of the refining section and rotated at a high speed, for example approximately 1000 r.p.m. where shaft 19 rotates in the same direction at a speed of 750 rpm. A conical deflector on the shaft 19 may centrifugally throw the stock outwardly toward the cylindri-- cal perforated plate of the bowl so that water flows through the perforations thereof while a film of thickened stock accumulates on the interior of the bowl. The impeller blades may move at the same speed as the shaft 19 as in Patent No. 2,927,738, but the blades must slope in the opposite direction because of the higher speed of rotation of the bowl in order to feed the stock into the refining section of the machine.

It will be apparent that many modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. A rotary refining machine for refining fibrous material comprising a generally cylindrical shell having an abrasive liner with a generally cylindrical interior surface for abrading fibrous material and having an inlet end for receiving fibrous material and an outlet end for discharging the fibrous material after refining thereof,

a central shaft extending axially within said shell and being driven to rotate in a predetermined direction,

a number of rotor assemblies disposed at successive positions about said shaft and having respective backing members of substantial length and width with the length dimension extending generally in the circumferential direction aboutsaid shaft and with the width 6 dimension extending generally parallel to the axis of said shaft,

respective refining elements secured to said backing members and having radially outer surfaces of substantial length and width generally conforming in configuration to said interior surface of said liner and disposed in confronting relation thereto,

means comprising pivot shafts disposed generally parallel to said central shaft pivotally securing said backing members to said central shaft so that said backing members rotate with said central shaft in said predetermined direction and are pivotal about the respective pivot shafts to move said refining elements toward said abrasive liner in response to centrifugal force resulting from rotation of said central shaft,

means for supplying fibrous material to be refined to said inlet end of said shell and into the path of rotation of said rotor assemblies, and

material impelling vanes each secured to one of said backing members, said vanes each havin g an impelling surface disposed at an acute angle to the plane of rotation of the vane and facing generally toward the outlet end of said shell, with the impelling surface being inclined toward the outlet end of the shell when considered with respect to the direction from the leading edge of the impelling surface to the trailing edge of the impelling surface so as to impel fibrous ma-.

terial in the path of said vane toward the outlet end of said shell.

2. In 'a rotary refining machine comprising a generally cylindrical shell having an abrasive liner with a generally cylindrical interior surface for abrading fibrous material and having an inlet end for receiving fibrous material and an outlet end for discharging the fibrous material after refining thereof, a central shaft extending axially within said shell and being driven to rotate in a predetermined direction, a number of rotor assemblies disposed at successive positions about said shaft and having respective backing members of substantial length and width with a the length dimension extending generally in the circumferential direction about said shaft and with the width dimension extending generally parallel to the axis of said shaft, respective refining elements secured to said backing members and having radially outer surfaces of substantial length and width generally conforming in configuration to said interior surface of said liner and disposed in confronting relation thereto, means for securing said backing members to said central shaft so that said backing members rotate with said central shaft in said predetermined direction while being movable in response to centrifugal force toward said abrasive liner, and means for adjustably determining the minimum clearance between the radially outer surfaces of said'refining elements and said interior surface of said liner;

means for supplying fibrous material to be refined to said inlet end of said shell and into the path of rotation of said rotor assemblies, and material impelling vanes each secured to one of said backing members, said vanes each having an impelling surface disposed at an acute angle to the plane of rotation of the vane and facing generally toward the outlet end of said shell, with the impelling surface being inclined toward the outlet end of the shell when considered with respect to the direction from the leading edge of the impelling surface to the trailing edge of the impelling surface so as to impel fibrous material in the path of said vane toward the outlet end of said shell. 3. The rotary refining machine of claim 1 with at least certain of said material impelling vanes being disposed in advance of respective refining elements with respect to said predetermined direction of rotation and being disposed toward the side of said backing members nearest said inlet end of said shell with the impelling surface of a certain vane in advance of a given refining element being secured to the backing member supporting the given refining element and tending to impel said fibrous material axially into the path of said given refining element.

4. The rotary refining machine of claim 1 with certain of said material impelling vanes being disposed in advance of respective refining elements with respect to said predetermined direction of rotation and being disposed toward the side of said backing members nearest said inlet end of said shell so that the impelling surface of a certain vane in advance of a given refining element tends to impel said fibrous material axially into the path of said given refining element and with additional material impelling vanes disposed in axial alignment with respective ones of said certain material impelling vanes and disposed closer to the outlet side of said backing members than said certain material impelling vanes.

5. In a rotary refining machine comprising a generally cylindrical shell having an abrasive liner with a generally cylindrical interior surface for abrading fibrous material and having an inlet end for receiving fibrous material and an outlet end for discharging the fibrous material after refining thereof, a central shaft extending axially within said shell and being driven to rotate in a predetermined direction, a number of rotor assemblies disposed at successive positions about said shaft and having respective backing members of substantial length and width with the length dimension extending generally in the circumferential direction about said shaft and with the width dimension extending generally parallel to the axis of said shaft, respective refining elements secured to said backing members and having radially outer surfaces of substantial length and width generally conforming in configuration to said interior surface of said liner and disposed in confronting relation thereto, means for securing said backing members to said central shaft so that said J backing members rotate with said central shaft in said predetermined direction while being movable in response to centrifugal force toward said abrasive liner, and means for adjustably determining the minimum clearance between the radially outer surfaces of said refining elements and said interior surface of said liner;

means for supplying relatively high density fibrous material having a density on an air dry basis of the order of 9% to said inlet end of said shell and into the path of movement of said rotor assemblies, and material impelling vanes each secured to one of said backing members, said vanes each having an impelling surface disposed at an acute angle to the plane of rotation of the vane and facing generally toward the outlet end of said shell, with the impelling surface being inclined toward the outlet end of the shell when considered with respect to the direction from the leading edge of the impelling surface to the trailing edge of the impelling surface so as to impel fibrous material in the path of said vane toward the outlet end of said shell.

References Cited by the Examiner UNITED STATES PATENTS 2,475 ,869 7/ 1949 Arpin 241294 2,649,718 8/1953 Arpin 24l-256 2,717,742 9/1955 Weigham 214255 2,902,228 9/1959 Higer 241257 2,927,738 3/1960 Arpin 241- 3,076,611 2/1963 Jordan 241-257 3,128,051 4/1964 Smith 241257 LESTER M. SWINGLE, Primary Examiner.

J. SPENCER OVERHOLSER, ROBERT C. RIORDON,

Examiners. H. F. PEPPER, IR., Assistant Examiner. 

1. A ROTARY REFINING MACHINE FOR REFINING FIBROUS MATERIAL COMPRISING A GENERALLY CYLINDRICAL SHELL HAVING AN ABRASIVE LINER WITH A GENERALLY CYLINDRICAL INTERIOR SURFACE FOR ABRADING FIBROUS MATERIAL AND HAVING AN INLET END FOR RECEIVING FIBROUS MATERIAL AND AN OUTLET END FOR DISCHARGING THE FIBROUS MATERIAL AFTER REFINING THEREOF, A CENTRAL SHAFT EXTENDING AXIALLY WITHIN SAID SHELL AND BEING DRIVEN TO ROTATE IN A PREDETERMINED DIRECTION, A NUMBER OF ROTOR ASSEMBLIES DISPOSED AT SUCCESSIVE POSITIONS ABOUT SAID SHAFT AND HAVING RESPECTIVE BACKING MEMBERS OF SUBSTANTIAL LENGTH AND WIDTH WITH THE LENGTH DIMENSION EXTENDING GENERALLY IN THE CIRCUMFERENTIAL DIRECTION ABOUT SAID SHAFT AND WITH THE WIDTH DIMENSION EXTENDING GENERALLY PARALLEL TO THE AXIS OF SAID SHAFT, RESPECTIVE REFINING ELEMENTS SECURED TO SAID BACKING MEMBERS AND HAVING RADIALLY OUTER SURFACES OF SUBSTANTIAL LENGTH AND WIDTH GENERALLY CONFORMING IN CONFIGURATION TO SAID INTERIOR SURFACE OF SAID LINER AND DISPOSED IN CONFRONTING RELATION THERETO, MEANS COMPRISING PIVOT SHAFTS DISPOSED GENERALLY PARALLEL TO SAID CENTRAL SHAFT PIVOTALLY SECURING SAID BACK- 